This invention is substantially an improvement over the invention set forth in U.S. patent application Ser. No. 813,655, which was filed on Dec. 26, 1985 by Jia-Ming Shyu under the title of "Automatic Treadmill". The aforesaid disclosure provides a treadmill with the features of controlling, detecting and displaying the exercise data with a micro-computer. The present invention relates to the improvements on the driving and slope adjusting mechanism of the tread belt, and the snap connection and disconnection device between the micro-computer control unit support and the handrail. These means are certainly suitable for other kinds of treadmills.
For conventional treadmills, the transmission mechanism of the tread belt may contain stepped wheels for the stage transmission only.
In order to obtain a stepless transmission, a transmission motor, such as a DC motor or an AC motor controlled with a frequency-changing controller, has to be used; however, either the DC motor or the frequency-changing unit will take up a considerable space within the machine. Moreover, the AC motor controlled with the frequency-changing unit would suffer from insufficient torsional force at a low speed, i.e. being unable to start at zero speed and to operate at a low speed.